Heat exchanger



P 1953 J. A. STAHN ETAL 2,653,7 99

HEAT EXCHANGER Filed Nov. 12, 1949 2 Sheets-Sheet 2 mlif Patented Sept. 29, 1953 HEAT EXCHANGER James A. Stahn and Joe 0. Shaw, Racine, Wis., assignors to Young Radiator Company, Racine, Wis., a corporation of Wisconsin Application November 12, 1949, Serial N 0. 126,803

The recent developments in heat-generating engines for powering large-sized land vehicles and airsea-craft has created a demand for regenerators or recuperators and exhaust gas heat-exchangers designed to use the high tem- 'perature exhaust from the engines for preheating in-corning air-flow required for purposes incident to the efiective operation of such vehicles and craft. Among the requirements for such pre heated air-flow are the more efficient combustion of turbine fuel, cabin heating, and wing and carburetor de-icing. For certain types of engine the temperature of the exhaust gas may be as great as 1800 degrees Fahrenheit. Using such gases an attempt is made to raise the temperature of the Lin-coming air-flow to 300-560 degrees Fahrenheit. To be acceptable for some of the aforesaid purposes, a heat-exchanger must have an extensive amount of heat-exchange surface in order to effect th desired heat transfer. Such transfer of heat can best be obtained from equipment using the small, closely-spaced, thin, metal tubes or passages which generally have been employed in the production of heatexchange units for the transfer of heat between the mor moderate-temperature fluids. However, working \vith'these higher temperatures presents the manufacturer of equipment with problems'of thermal expansive and contractive forces not heretofore encountered in the production of heatexchange equipment for moderate-temperature heating or cooling media. I

The main objects of this invention, therefore,

are to provide an improved form of heatexchanger for use in exposing an iii-coming airflow to the heat of exhaust gases from a heat.- generating engine for the purpose of pro-heating said air-flow to make it utilizable for special purposes incident to the operation of the engine and/or the vehicle or or it which the engine powers; to provide an improved expansion mounting for heat-exchangers of this type which will allow for the comparatively excessive expansion and contraction forces to which such an ex changer will be subjected; to provide an improved expansion mounting especially suitable for large sized heat-exchangers of the type known regenerators and which are required for turbines powering railroad. locomotives; and to provide an improved form of expansion-mounted heatexchanger of this kind which is comparatively simple and economical to manufacture and which is highly efiicient in use. p

In the accompanying drawings two types. of heat-exchangers embodying this invention are shown;

2 Claims. (Cl. 257-236) Fig. 1 is a front elevation of a heat-exchanger, embodying this invention, of the type generally known as a regenerator. One corner thereof is broken away to more clearly indicate the form of the bellows which provides a part of the expansion mounting for the core-unit;

Fig. 2 is an enlarged, partly-sectional, partlyelevational view of the regenerator, as viewed from the plane of the line 2-2 of Fig. 1, showing in detail th manner of connecting the core-unit to the mounting members, whereby the regenerator is interposed between transversely disposed conduit sections adapted to direct the flow of gases and air through the core labyrinth and tubes, respectively;

Fig. 3 is a front elevation of a smaller-size heatexchanger of the type required for pro-heating an incoming air-flow for cabin heating and/or wing or carburetor de-icing;

Fig. 4 is a side elevation of the same;

Fig. 5 is an enlarged, fragmentary, crosssectional detail taken on the line 55 of Fig. 3 showing the bellows construction which provides an expansion mounting for the core unit; and

Fig. 6 is an enlarged fragmentary detail taken on the line 66 of Fig. 4 showing the arcuate corner construction of the bellows.

A heat-exchanger embodying this invention and suitablefor pre-heating air for any of the aforesaid purposes, comprises a core-unit I made up of one or more sections supported on mounting members 8 and 9, whereby it is interposed between the ends of transversely disposed conduit sections which direct the exhaust gases and'the air-flow through the core-unit. Between the core-unit and at least one of the mounting members is arranged an air-sealed, expansion connection it which permits the relative shifting of the coreunit and mounting member to accommodate the excessive expansive and contractive forces to which said core-unit is subjected.

Each core-unit section comprises a battery or bundle of thin, metal tubes 1 i arranged in parallel, spaced relationship spanning and bonded at their ends to header plates l2, so as to provide an air-flow labyrinth 43 around the tubes ll between the header plates l2.

'The core-unit l for the regenerator type of heat-exchanger has to be a rather massive structure because of the volume of gas and air that have to be handled. Thus, as shown in Figs. 1 and 2,the core-unit 1 is a fabrication of a plurality of these core-unit sections of rather considerable length. As indicated, the sections are arranged in rows and bonded together within embracing rectangular-members I 4 between hori- 3 zontal and vertical reinforcing cross-braces l5 and 16, thereby forming an elongated structure of rectangular cross-section.

The core-unit l, for the smaller type heatexchanger, as shown in Figs. 3-6, may be a single section. The perimetrical portions of the header plates 12 are extended beyond the outer rows of tubes II a greater distance than with the regenerator type. Moreover, the header plate 12, wherewith the air-sealed expansion connection I8 is associated, is formed slightly different from the header plates employed in the core-unit sec tions for the regenerator-type of exchanger in that plate l2, for the smaller type heat exchanger, adjacent the perimeter is disposed transversely to the plane of the plate and then extended outwardly to provide an L-shaped border flange. The regenerator header plate I2 has merely a transverse flange.

The mounting members 8 and 8 for the two types of exchangers shown in the drawings differ materially in form. However, they have essentially the same function. In either modification, these mounting members are spanned and connected together on two sides by plates l1 (and in the case of the regenerator, channel bars l8) which constitute closures for the opposite sides of the labyrinth l3, and serve to channel the exhaust gases from the engine through the labyrinth.

For the regenerator-type of heat-exchanger, the mounting members 8 and 9, as herein shown, are respectively channel-form and Z-form. For the smaller-type of heat-exchanger the mounting members 8 and 9 are respectively a sleeve and a flanged open rectangle.

The channel-form mounting-member 8 has its outer flange l9 slightly wider than the inner flange 20. The base of the member 8 is bonded to the retaining member H. The outer flange I9 is provided with a row of apertures 2| bordering the perimeter thereof. This permits the mounting member 8 to be attached to a similar flange on the end of a section of a conduit which directs the air-flow through the tubes H for heating by the gases passing through the labyrinth 13. The inner, vertical flange 28 on opposite sides of the core-unit 1 has bonded thereto a perforated bar 22, which provides for a connection of the regenerator to the opposed ends of sections of a conduit leading from the exhaust of an engine and to the atmosphere, respectively.

The z-form mounting-member 8 is positioned with the inner leg 23 embracing the retaining member [4 and its outer leg 24 spaced circumferentially outward therefrom. The core-unit I is shiftably supported on the leg 23 by a rib or bead 25 constituting a part of the air-sealed expansion connection I8 for one end of the core-section, as will be explained more fully hereinafter. The leg 23 has secured to each of the opposite sides thereof a perforated plate or bar 26, which bars co-act with the bars 22 for attaching the exchanger to the exhaust gas conduit sections hereinbefore referred to.

A transversely-disposed ring plate 21 is bonded to the edge of the outer leg 24 of the mounting member 9. This is provided with perforations 28 and a reinforcing bar 29 for connection thereof to a section of the conduit which directs the in-coming air through the tubes H, as hereinbefore indicated. Incidentally, the positioning of the plate 21 on the leg 24 of the mounting member 9 provides a chamber 30 perimetricall of the adjacent header plate l2, wherein is located the bellows forming a part of the air-sealed expansion connection ill, to be more fully described hereinafter.

The sleeve mounting member 8, (for the modification shown in Figs. 3-6) telescopes with the flange on the adjacent header plate l2 and is bonded thereto (see Fig. 5). Suitable means are provided for attaching the sleeve to one end of a section of conduit for conveying air through the tubes ll.

The flanged mounting-member 9 is bonded to the side plates 11, and mounts a funnel 3 I, wherebythe exchanger is connected to the end of a section of the aforesaid conduit which conveys air through the tubes I l of the core-unit I.

At opposite sides, the mounting-members 8 and 8 have perforated rectangular members 32 secured thereto, whereby the exchanger is attached to the ends of opposed sections of a conduit for directing the flow of exhaust gases through the core labyrinth 43.

The air-sealed expansion connection ID, as herein shown, comprises a bellows made up of a plurality of sheet metal stampings in the form of rectangular members bonded together along their perimeters. Two or more pairs of these opposed stampings have their opposite end stampings respectively secured to one end of the core-unit 1 and the contiguous mounting-member which, as herein shown, is the mountingmember 8.

For the regenerator-type exchanger, the end members for the bellows are secured to the binding member l4 and the inner perimeter of the ring plate 21 and provides an air-seal between the respective conduit passages through the tubes H nd the labyrinth I8. Thus the weight of the core-unit I is borne directly by the mountingmember 8, the head 25 affording the required relative shifting of the core-unit l with respect to the mounting-member.

For the small-type exchanger, the end members of the bellows are attached respectively to the perimeter of the header plate l2 and the mounting-member 9. Hence, in this type, the bellows directly carries the weight of that end of the core-unit 1. As will be apparent from Fig. 5 the relative form and arrangement of the mounting member 8 and the header plate [2 provide a chamber perimetrically of the header plate in which chamber is located the bellows constituting a part of the expansive connection l8.

At the corners of the mounting-members 8 and 9 there is, of necessity, an accumulation of stress. However, these mounting-members can be and are made of comparatively heavy material so that they can resist these strains without injury or distortion of said members.

The bellows material being necessarily thin metal could not absorb or resist the stress accumulations to which they might be directly subjected or which might be communicated to them from the respective mounting-members or the core-units, if they were made with square corners. Therefore, the otherwise rectangular members for the bellows are made of arcuate form at the corners, as clearly shown in the drawings. This permits the corner stresses to be more readily dissipated through the contiguous portions of the bellows, and free the bellows from the likelihood of corner fracture.

Variations and modifications in the details of structure and arrangement of the parts may be resorted to within the spirit and coverage oi the appended claims.

We claim:

1. In a heat-exchanger 01 the class described, the combination of a heat-transfer core-unit comprising a battery of tubes arranged in spaced parallel relationship spanning and bonded at their ends to rectangularly shaped header plates so as to form an air-flow labyrinth around said tubes intermediate said plates, rectangularly shaped mounting members for interposing said core-unit between opposed ends of conduit sections adapted to direct heat-exchanging air flows through said tubes and said labyrinth, and a rectangularly shaped bellows connecting one of said header plates and one of said mountingmembers to provide an air-sealed yielding-connection permitting a relative movement of said plate and member to accommodate the expansive and contractive forces to which said core-unit is subjected, said bellows having the perimetrical portions thereof adjacent the corners of said one header plate and mounting member materially arcuate-shaped so as to minimize the likelihood of fracture of said bellows adjacent said corners where stress is accumulated.

2. In a heat-exchanger for using the hightemperatured exhaust gases from an engine to preheat an incoming air flow, the combination of an elongated heat-transfer core-unit of rectangular cross-section fabricated from a plurality of separately-formed core-sections arranged in superimposed rows and each comprising a battery of tubes arranged in spaced parallel relationship spanning and bonded at their ends to header plates, rectangularly-shaped retaining members bonded to the peripheral portions of the header plates of the outer rows of core sections, a pair of rectangularly-shaped mounting members each embracing one of said retaining members for interposing said coreunit between the opposed ends of conduit sections adapted to direct air flows through said labyrinth and said tubes, a rib formed on one of the aforesaid embracing members to provide a minimum-friction shifting contact between said members to permit relative movement of said members to accommodate the expansive and contractive forces to which said core-unit is subjected, and a rectangularly-shaped, bellows forming an air-sealed yielding connection between the aforesaid embracing members, said bellows having the perimetrical portions adjacent the four corners of said core-unit rounded so as to lessen the probability of fracture produced by stress accumulations at these points.

JAMES A. STAHN. JOE C. SHAW.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,489,932 Dickey Apr. 8, 1924 1,594,199 Heineman July 27, 1926 1,604,197 Rushmore Oct. 26, 1926 1,724,351 Henderson et al. Aug. 13, 1929 1,815,618 Graham July 21, 1931 1,875,663 Sandstrom Sept. 6, 1932 1,918,966 Harkness July 18, 1933 1,921,988 Govers Aug. 8, 1933 1,922,173 Pedersen Aug. 15, 1933 2,232,936 Bimpson Feb. 25, 1941 2,344,269 Saco, Jr. Mar. 14, 1944 2,375,999 Miller May 15, 1945 2,487,626 Wittman Nov. 8, 1949 FOREIGN PATENTS Number Country Date 100,671 Great Britain June 22, 1916 591,699 Great Britain Aug. 26, 1947 

